Ultrasound is a sound wave with a frequency higher than 20000 Hz. It has good directionality and strong penetrating ability, is easy to obtain relatively concentrated sound energy, has a long distance of propagation in water, and can be used for distance measurement, speed measurement, cleaning, welding, stone crushing, and sterilization. There are many applications of ultrasound in medicine, military, industry and agriculture. Ultrasound is non-polluting and noiseless, and will not cause any harmful effect on the environment. The transmission speed of sound is different in liquids with different concentrations. Therefore, ultrasound can be used to achieve on-line detection of liquid concentrations.
In the related art, ultrasound has been widely used in the detection of the concentration of various liquids. However, the ultrasound concentration detection in the related art is susceptible to interference from the outside, for instance, factors such as the interference of air bubbles and other impurities, the variation of the flow velocity, and the like all affect the accuracy of the measurement results.